Digital-Research-Source-Code/CPM OPERATING SYSTEMS/CPM 68K/1.2 SOURCE/1/BDOSDEF.H

/********************************************************
*							*
*		CP/M-68K header file 			*
*    Copyright (c) 1982 by Digital Research, Inc.	*
*    Structure definitions for BDOS globals		*
*	and BDOS data structures			*
*							*
********************************************************/

/**************************************************************************
The BDOS data structures, especially those relating to global variables, 
are structured in a way that hopefully will enable this BDOS, in the future,
to easily become a re-entrant multi-tasking file system.  Consequently, 
the BDOS global variables are divided into two classes.  Those that are
truly global, even in the case of multiple tasks using the file system
concurrently, are simply declared as global variables in bdosmain.c.
Only a few "globals" are really global in this sense.

The majority of the "global" variables are actually state variables that
relate to the state of the task using the file system.  In CP/M-68K, these
are "global", since there's only one task, but in a multi-thread model they're
not.  These type of variables are put into a data structure, with the
intention that in the multi-task environment this structure will be based.

The following declarations take this philosophy into account, and define
a simple structure for the single thread environment while leaving the
possibilities open for the multi-thread environment.
****************************************************************************/

#define snglthrd TRUE
			/* TRUE for single-thread environment
			FALSE to create based structure for re-entrant model */
#if snglthrd
#define GBL gbls 
				/* In single thread case, GBL just names
					the structure */
#define BSETUP  EXTERN struct stvars gbls;
				/* and BSETUP defines the extern structure */
#endif

#if ! snglthrd
#define GBL (*statep)
				/* If multi-task, state vars are based */
#define BSETUP  REG struct stvars *statep; \
	  statep = &gbls;
				/* set up pointer to state variables */
			/* This is intended as an example to show the intent */
#endif


/* Note that there are a few critical regions in the file system that must 
   execute without interruption.  They pertain mostly to the manipulation of
   the allocation vector.  This isn't a problem in a single-thread model, but
   must be provided for in a multi-tasking file system.  Consequently, the
   primitives LOCK and UNLOCK are defined and used where necessary in the 
   file system.  For the single thread model, they are null routines       */

#define LOCK    /**/ 
#define UNLOCK  /**/
/* Be sure LOCK and UNLOCK are implemented to allow recursive calls to LOCK.
   That is, if a process that calls LOCK already owns the lock, let it proceed,
   but remember that only the outer-most call to UNLOCK really releases the
   file system.		*/

 
#define VERSION 0x2022		/* Version number for CP/M-68K  */
#define robit 0			/* read-only bit in file type field of fcb */
#define SECLEN 128		/* length of a CP/M sector	*/


/* File Control Block definition */
struct fcb
{
	UBYTE	drvcode;	/* 0 = default drive, 1..16 are drives A..P */
	UBYTE	fname[8];	/* File name (ASCII)			*/
	UBYTE	ftype[3];	/* File type (ASCII)			*/
	UBYTE	extent;		/* Extent number (bits 0..4 used)	*/
	UBYTE	s1;		/* Reserved				*/
	UBYTE	s2;		/* Module field (bits 0..5), write flag (7) */
	UBYTE	rcdcnt;		/* Nmbr rcrds in last block, 0..128	*/
	union
	{
	  UBYTE	small[16];	/* 16 block numbers of 1 byte		*/
	  WORD	big[8];		/* or 8 block numbers of 1 word		*/
	}	dskmap;
	UBYTE	cur_rec;	/* current record field			*/
	UBYTE	ran0;		/* random record field (3 bytes)	*/
	UBYTE	ran1;
	UBYTE	ran2;
};


/* Declaration of directory entry	*/
struct dirent
{
	UBYTE	entry;		/* 0 - 15 for user numbers, E5 for empty */
				/* the rest are reserved		*/
	UBYTE	fname[8];	/* File name (ASCII)			*/
	UBYTE	ftype[3];	/* File type (ASCII)			*/
	UBYTE	extent;		/* Extent number (bits 0..4 used)	*/
	UBYTE	s1;		/* Reserved				*/
	UBYTE	s2;		/* Module field (bits 0..5), write flag (7) */
	UBYTE	rcdcnt;		/* Nmbr rcrds in last block, 0..128	*/
	union
	{
	  UBYTE	small[16];	/* 16 block numbers of 1 byte		*/
	  WORD	big[8];		/* or 8 block numbers of 1 word		*/
	}	dskmap;
};


/* Declaration of disk parameter tables		*/
struct dpb			/* disk parameter table		*/
{
	UWORD	spt;		/* sectors per track 		*/
	UBYTE	bsh;		/* block shift factor		*/
	UBYTE	blm;		/* block mask			*/
	UBYTE	exm;		/* extent mask			*/
	UBYTE	dpbdum;		/* dummy byte for fill		*/
	UWORD	dsm;		/* max disk size in blocks	*/
	UWORD	drm;		/* max directory entries	*/
	UWORD	dir_al;		/* initial allocation for dir	*/
	UWORD	cks;		/* number dir sectors to checksum */
	UWORD	trk_off;	/* track offset			*/
};

struct	dph			/* disk parameter header	*/
{
	UBYTE	*xlt;		/* pointer to sector translate table	*/
	UWORD	hiwater;	/* high water mark for this disk	*/
	UWORD	dum1;		/* dummy (unused)			*/
	UWORD	dum2;
	UBYTE	*dbufp;		/* pointer to 128 byte directory buffer	*/
	struct dpb *dpbp;	/* pointer to disk parameter block	*/
	UBYTE	*csv;		/* pointer to check vector		*/
	UBYTE	*alv;		/* pointer to allocation vector		*/
};


/* Declaration of structure containing "global" state variables */
struct stvars
{
	struct dph *dphp;	/* pointer to disk parm hdr for cur disk   */
	struct dirent *dirbufp; /* pointer for directory buff for process  */
				/* stored here so that each process can	   */
				/* have a separate dirbuf.		   */
	struct dpb *parmp;	/* pointer to disk parameter block for cur */
				/* disk. Stored here to save ref calc	   */
	UBYTE	*dmaadr;	/* Disk dma address			   */
};



};